Retina iMac 27" Late 2014 - Link to Apple Support Appears When Trying to Boot Into Installer

I'm trying to upgrade my Retina iMac from late 2014 from its latest supported Big Sur version to Ventura. I've done everything correctly according to the guide I've followed (OpenCore's own guide). When it comes to restarting the computer and getting into the boot menu, I see three alternatives; my regular Mac (SSD) drive, my Windows (Boot Camp) partition and then the Venura installer.

After choosing the Ventura installer, it leads me to a black screen showing a web link to: support.apple/mac/startup. I've tried this several times and get the same issue. Do you guys know what I need to do to go forward?

Thanks!